Mass. AD project breaks ground at existing landfill gas plant

By CommonWealth Resource Management Corp. | February 28, 2014

Construction has begun at the Crapo Hill Landfill in Dartmouth, Mass., on the CRMC Dartmouth Bioenergy Facility, an anaerobic digestion project developed by CommonWealth Resource Management Corporation in cooperation with the Greater New Bedford Regional Refuse Management District, the landfill owner. The Bioenergy Facility will produce biogas for use as a supplemental fuel by an existing 3.3-MW landfill gas-fired electric power generating facility at the landfill that is owned and operated by a CRMC subsidiary. That subsidiary currently purchases landfill gas from the District, and also leases the site at the landfill on which the two projects will be co-located.

In addition to producing biogas, operation of the Bioenergy Facility at the Landfill is expected to enable the District, a public entity whose members include the Town of Dartmouth and the City of New Bedford, Mass., to adapt to changes in the state’s solid waste management regulations regarding food wastes and other organics. An impending ban on the disposal of such materials generated by commercial sources could have a long-term effect on the district’s landfilling operations and its position in the regional solid waste marketplace.

The Bioenergy Facility is the first of its kind to be sited at an operating Massachusetts landfill, and the first developed in the state to produce biogas for use in an existing landfill gas-to-energy facility.

The project will be constructed in two phases. In its initial pilot phase, the facility is sized to accept approximately 3,000 gallons per day of the targeted organic wastes for processing and digestion (over a 30 day retention period) in a digester with 100,000 gallons of holding capacity. The quantity of biogas expected to be produced through Pilot operations can be utilized within the current power generating capacity of the existing landfill gas facility.

If successful, the Pilot scale Bioenergy Facility will be expanded 10-fold to enable processing and digestion of up to 30,000 gallons per day of feedstock (over a 30 day retention period) in a digester with 1.0 to 1.2 million gallons of holding capacity. The quantity of biogas expected to be produced through this anticipated second phase of project operations would be sufficient to support a 25 percent increase in the generating capacity of the existing landfill gas-fired power plant — from 3.3 MW to 4.1 MW.

The two facilities will operate symbiotically in what is often referred to as a virtuous cycle. While biogas produced by the Bioenergy Facility will help fuel the landfill gas facility, the power produced by, and waste heat recovered from, the power plant’s generators will be used to satisfy the Bioenergy Facility electric and thermal energy requirements.

In addition, the pilot phase of the Bioenergy Facility project will be used to test the feasibility of making beneficial use of some portion of the residuals (spent digestate) from the anaerobic digestion process within existing operations at the landfill. The beneficial uses to be demonstrated include the provision of a biologically enriched admixture for yard waste composting; displacing water as the source of moisture in the production of daily landfill cover material; and stimulating landfill gas production and capture through controlled inoculation of digestate in a previously closed area of the landfill.

In addition to CRMC’s own capital investment, the Bioenergy Facility project is being funding in part by grants and loans from the Massachusetts Clean Energy Center, the Massachusetts Recycling Loan Fund, and the USDA Rural Development agency.

Users of the Bioenergy Facility are expected to include supermarket chains, food processors, schools, hospitals and other commercial and institutional entities that generate food wastes, as well as waste haulers that collect and transport food wastes, fats, oils and greases, and biosolids for disposal.